In a late-game team fight scenario, when is it optimal to focus a tank instead of a high-damage carry?

In a late-game team fight scenario, it is optimal to focus a tank instead of a high-damage carry when the tank is significantly out of position, is preventing access to the enemy's backline, or possesses a critical crowd control ability that must be neutralized immediately. Focusing the tank is correct when they are isolated from their team and vulnerable to a quick burst of damage. This can occur if the tank has overextended while trying to initiate or has been caught out of position due to poor vision. Eliminating the tank in this situation can create a numbers advantage for your team and make it easier to engage on the remaining enemy heroes. Secondly, focusing the tank is the correct play if they are effectively blocking access to the enemy's backline, preventing your team from reaching the high-damage carries. If the tank is positioned in a way that makes it impossible to attack the carries without first eliminating them, then focusing the tank becomes necessary. Finally, the tank should be focused if they possess a critical crowd control ability, such as a long-duration stun or a team-wide knock-up, that can significantly disrupt your team's formation or allow the enemy to easily engage. Eliminating the tank before they can use this ability can prevent a devastating team fight loss. It is generally not optimal to focus the tank if the enemy carries are easily accessible and are dealing significant damage, unless one of these conditions is met.